Defense Post Range and Placement
An OpenFront defense post multiplies attacker losses by 5 and slows them by 3 within 30 tiles. Overlapping posts do not stack — the code stops at the first one it finds.
The short version
- ×5 attacker losses and ×3 slower within 30 tiles. First one costs 50,000
- They do not stack — the game stops at the first post it finds
- Boats do not bypass them. The check is on the tile being taken, not where you came from
A defense post multiplies attacker losses by 5 and slows their advance by 3 within a 30-tile radius. The first one costs 50,000, making it the best gold-per-effect building in the game.
But overlapping posts do not stack. Two posts covering the same tile still give exactly ×5.
The numbers
| Item | Value |
|---|---|
| Protection radius | 30 tiles |
| Attacker loss multiplier | ×5 |
| Attacker speed multiplier | ×3 slower |
| First cost | 50,000 |
| Subsequent | min(250,000, (n+1) × 50,000) |
| Build time | 5 seconds |
| Upgradeable | No |
Protected borders render with a checkered pattern. Check visually after placing.
They do not stack — here is why
The game scans the 30 tiles around the attacked tile, and the moment it finds one defense post owned by the defender it applies the multipliers and stops. It never looks at the second.
So packing posts together is wasted gold. If you are building two, separate them by more than 30 tiles so they cover different ground.
Buildings only need 15 tiles of clearance, so you can place them 15 apart — but then their coverage overlaps heavily and the second post is worth less than half.
Where to put them
A defense post blocks corridors, not area.
Good
- The neck of a peninsula
- A mountain pass
- A river or strait crossing
- The isthmus joining two landmasses
Bad
- Open plains — 30 tiles covers only a fraction of that border
- Deep interior — protecting ground nobody attacks
- Anywhere already inside another post’s radius
If the terrain lets one post seal an entire approach, 50,000 gold frees every troop on that side to fight elsewhere. That is why it is the best early-to-mid value in the game.
The myth — “boats bypass defense posts”
They do not. This one is widely repeated, and the code disagrees.
When a boat lands, the game creates an ordinary attack starting from the landing tile. The defense post check does not care where the attack originated — it only asks whether the tile being taken is within 30 tiles of a post.
Land next to a post and you eat the same ×5 as any ground attack.
What boats actually buy you:
- The landing tile is free. Normal combat begins after that
- You can choose a coast with no post. That is what going around really means
- Landing simultaneously with a ground push splits the defense
So before committing a boat, look for coastline without the checkered pattern. Up to 3 boats at once; a warship kill means total loss of the troops aboard, and warship patrol range is 100 tiles.
How many?
| Situation | Recommendation |
|---|---|
| One or two land approaches | 1–2. Seal the necks and you are done |
| Open on all sides | Prefer troops and cities over posts |
| Island / peninsula | One at the likely landing zone, rest into ports |
| Large late-game empire | One per major corridor, 30+ tiles apart |
Costs run 50,000 → 100,000 → 150,000 → 200,000 → 250,000 and then cap. The building cost calculator totals any batch.
Once your defense post spending passes the price of a city (125,000), stop and think. A city adds +250,000 to your troop cap, and those troops are also defense. See How Many Cities Should You Build?.
More
- Combat Math — terrain, encirclement, retreating
- What Attack Ratio Should You Use? — punch through or go around
- All Six Buildings — everything else